1. Field of the Invention
The invention relates to a video tape recorder (VTR) for recording and reproducing video signals and audio signals and, more particularly, to a video tape recorder which can simultaneously record a plurality of video signals and audio signals onto the same tape by a single tape running mechanism and can also reproduce a desired signal.
2. Description of the Related Art
In recent years, the widespread proliferation of home-use VTRs is remarkable. However, when video images of a television broadcasting are recorded, it is impossible to simultaneously record video signals of a plurality of channels by one VTR. Such a drawback is felt to be further inconvenient due to the recent developments of the satellite broadcasting BS and the cable television CATV.
As a conventional method of recording a plurality of video signals by one VTR, there is a method called a field skip. For instance, a prior art technique is taught in JP-A-59-117383. FIG. 1 shows a prior art construction of a video tape recorder. Video signals given to input terminals 21 and 22 are synchronized by a delay circuit 25 and a control circuit 26. A synthesis signal in which the respective input signals are alternately rearranged by every field by a select circuit 24 is obtained and is recorded by a rotary head 30 through a recording circuit 29. In the reproducing operation, the synthesis signal reproduced by a playback circuit 31 is delayed to form a delayed signal by a delay circuit 32. Each of the video signals is obtained from the synthesis signal and the delayed signal selected by a select circuit 33. However, in such a field skip recording, since each of the video signals is recorded every other field, the video information is intermittently reproduced and there is a drawback such that the reproduced image becomes unnatural. Even in the case of a line skip method in which the input signals are rearranged every line, there is a problem such that a vertical resolution of the reproduced image deteriorates.
As a method of recording all information instead of the field skip, there is a method of recording a plurality of video signals by using a plurality of head pairs as disclosed in JP-A-63-280589. FIG. 2 shows a tape pattern based on the above method. A signal of the R channel is recorded by the pair of rotary heads having azimuth angles of .+-..theta. and a signal of the L channel is recorded by the pair of rotary heads having different azimuth angles .+-..theta.. In the above case, although the recording and reproduction can be performed by a customer, when the signal on the tape recorded by such a VTR is reproduced by the conventional VTR, the signal of only one selected channel can be reproduced and there is a large problem in terms of the compatibility.
The conventional technique as mentioned above is insufficient to record and reproduce a plurality of video signals and audio signals and is not put-into practical use as a home-use VTR.